Merge pull request #10868 from mshabunin:sample-bgsegm

* Samples: reworked bgfg_bgsegm

* fixup! Samples: reworked bgfg_bgsegm

samples/cpp/bgfg_segm.cpp

 #include "opencv2/core.hpp"
-#include <opencv2/core/utility.hpp>
 #include "opencv2/imgproc.hpp"
-#include "opencv2/video/background_segm.hpp"
+#include "opencv2/video.hpp"
 #include "opencv2/videoio.hpp"
 #include "opencv2/highgui.hpp"
-#include <stdio.h>
+#include <iostream>
 
 using namespace std;
 using namespace cv;
 
-static void help()
-{
- printf("\nDo background segmentation, especially demonstrating the use of cvUpdateBGStatModel().\n"
-"Learns the background at the start and then segments.\n"
-"Learning is togged by the space key. Will read from file or camera\n"
-"Usage: \n"
-"			./bgfg_segm [--camera]=<use camera, if this key is present>, [--file_name]=<path to movie file> \n\n");
-}
-
-const char* keys =
-{
-    "{c  camera   |         | use camera or not}"
-    "{m  method   |mog2     | method (knn or mog2) }"
-    "{s  smooth   |         | smooth the mask }"
-    "{fn file_name|../data/tree.avi | movie file        }"
-};
-
-//this is a sample for foreground detection functions
 int main(int argc, const char** argv)
 {
-    help();
-
+    const String keys = "{c camera||use video stream from camera (default is NO)}"
+                        "{fn file_name|../data/tree.avi|video file}"
+                        "{m method|mog2|method: background subtraction algorithm ('knn', 'mog2')}"
+                        "{h help||show help message}";
     CommandLineParser parser(argc, argv, keys);
+    parser.about("This sample demonstrates background segmentation.");
+    if (parser.has("help"))
+    {
+        parser.printMessage();
+        return 0;
+    }
     bool useCamera = parser.has("camera");
-    bool smoothMask = parser.has("smooth");
-    string file = parser.get<string>("file_name");
-    string method = parser.get<string>("method");
-    VideoCapture cap;
-    bool update_bg_model = true;
+    String file = parser.get<String>("file_name");
+    String method = parser.get<String>("method");
+    if (!parser.check())
+    {
+        parser.printErrors();
+        return 1;
+    }
 
-    if( useCamera )
+    VideoCapture cap;
+    if (useCamera)
         cap.open(0);
     else
         cap.open(file.c_str());
-
-    parser.printMessage();
-
-    if( !cap.isOpened() )
+    if (!cap.isOpened())
     {
-        printf("can not open camera or video file\n");
-        return -1;
+        cout << "Can not open video stream: '" << (useCamera ? "<camera 0>" : file) << "'" << endl;
+        return 2;
     }
 
-    namedWindow("image", WINDOW_NORMAL);
-    namedWindow("foreground mask", WINDOW_NORMAL);
-    namedWindow("foreground image", WINDOW_NORMAL);
-    namedWindow("mean background image", WINDOW_NORMAL);
-
-    Ptr<BackgroundSubtractor> bg_model = method == "knn" ?
-            createBackgroundSubtractorKNN().dynamicCast<BackgroundSubtractor>() :
-            createBackgroundSubtractorMOG2().dynamicCast<BackgroundSubtractor>();
+    Ptr<BackgroundSubtractor> model;
+    if (method == "knn")
+        model = createBackgroundSubtractorKNN();
+    else if (method == "mog2")
+        model = createBackgroundSubtractorMOG2();
+    if (!model)
+    {
+        cout << "Can not create background model using provided method: '" << method << "'" << endl;
+        return 3;
+    }
 
-    Mat img0, img, fgmask, fgimg;
+    cout << "Press <space> to toggle background model update" << endl;
+    cout << "Press 's' to toggle foreground mask smoothing" << endl;
+    cout << "Press ESC or 'q' to exit" << endl;
+    bool doUpdateModel = true;
+    bool doSmoothMask = false;
 
-    for(;;)
+    Mat inputFrame, frame, foregroundMask, foreground, background;
+    for (;;)
     {
-        cap >> img0;
-
-        if( img0.empty() )
+        // prepare input frame
+        cap >> inputFrame;
+        if (inputFrame.empty())
+        {
+            cout << "Finished reading: empty frame" << endl;
             break;
+        }
+        const Size scaledSize(640, 640 * inputFrame.rows / inputFrame.cols);
+        resize(inputFrame, frame, scaledSize, 0, 0, INTER_LINEAR);
 
-        resize(img0, img, Size(640, 640*img0.rows/img0.cols), 0, 0, INTER_LINEAR_EXACT);
+        // pass the frame to background model
+        model->apply(frame, foregroundMask, doUpdateModel ? -1 : 0);
 
-        if( fgimg.empty() )
-          fgimg.create(img.size(), img.type());
+        // show processed frame
+        imshow("image", frame);
 
-        //update the model
-        bg_model->apply(img, fgmask, update_bg_model ? -1 : 0);
-        if( smoothMask )
+        // show foreground image and mask (with optional smoothing)
+        if (doSmoothMask)
         {
-            GaussianBlur(fgmask, fgmask, Size(11, 11), 3.5, 3.5);
-            threshold(fgmask, fgmask, 10, 255, THRESH_BINARY);
+            GaussianBlur(foregroundMask, foregroundMask, Size(11, 11), 3.5, 3.5);
+            threshold(foregroundMask, foregroundMask, 10, 255, THRESH_BINARY);
         }
-
-        fgimg = Scalar::all(0);
-        img.copyTo(fgimg, fgmask);
-
-        Mat bgimg;
-        bg_model->getBackgroundImage(bgimg);
-
-        imshow("image", img);
-        imshow("foreground mask", fgmask);
-        imshow("foreground image", fgimg);
-        if(!bgimg.empty())
-          imshow("mean background image", bgimg );
-
-        char k = (char)waitKey(30);
-        if( k == 27 ) break;
-        if( k == ' ' )
+        if (foreground.empty())
+            foreground.create(scaledSize, frame.type());
+        foreground = Scalar::all(0);
+        frame.copyTo(foreground, foregroundMask);
+        imshow("foreground mask", foregroundMask);
+        imshow("foreground image", foreground);
+
+        // show background image
+        model->getBackgroundImage(background);
+        if (!background.empty())
+            imshow("mean background image", background );
+
+        // interact with user
+        const char key = (char)waitKey(30);
+        if (key == 27 || key == 'q') // ESC
         {
-            update_bg_model = !update_bg_model;
-            if(update_bg_model)
-                printf("Background update is on\n");
-            else
-                printf("Background update is off\n");
+            cout << "Exit requested" << endl;
+            break;
+        }
+        else if (key == ' ')
+        {
+            doUpdateModel = !doUpdateModel;
+            cout << "Toggle background update: " << (doUpdateModel ? "ON" : "OFF") << endl;
+        }
+        else if (key == 's')
+        {
+            doSmoothMask = !doSmoothMask;
+            cout << "Toggle foreground mask smoothing: " << (doSmoothMask ? "ON" : "OFF") << endl;
         }
     }
-
     return 0;
 }